Cancel Dropbox Trial

I have been trying for two days to cancel the trial before it goes to billing. I have tried all the steps shown here and even contacted Dropbox directly. They said because I selected the trial through the app, I have to go through Apple to stop the billing. I have been through the steps given on this link: support.apple.com/en-us/HT202039 and gone through the app and followed those directions. The option to cancel is never given at any point, only to buy more. I even tried deleting my account, but all that allowed me to do was to go back, not delete. I'm making a legitimate effort to cancel before the deadline and don't want to get charged. Please help!